The present invention relates to a method and apparatus for joining electric component pins and electric wires. The invention has great utility in but is not limited to joining insulated magnet wires to multipinned terminal blocks and non-insulated wire strands to multipinned terminals.
The art of joining wires to wires and wires to metal pins is quite old. The art of joining wires to wires to form pigtails or splices includes U.S. Pat. No. 4,687,900 wherein stranded wire 12 is joined to initially insulated magnet wire by placing these wires in the notch of a lower fusing electrode and joining them through the application of pressure, heat, and current through the engagement of the upper fusing electrode. Care is taken to locate the non-insulated stranded wires above and in contact with the insulated magnet wire so that the current path is completed through the wire 12 to the side walls of the lower electrode to generate electrode heat, for burning off the wire 14 insulation and establishing a current and heating path through both wires to be joined. A technical problem associated with this approach results from the wires being unsymmetrically placed or held in the notch. This approach may cause the initial application of fusing current and heat to the insulated wire 14 being unevenly applied to remove or burn off the insulation. This effect would cause non-uniform or unreliable joints from one termination to the next.
Attempts have been made for joining non-insulated wires to pins, however, these attempts experienced reproducability and reliability problems because it was difficult to position the small pin exactly centered on the wire. The pin usually shifted toward one side of the notch or the other causing the initial current to pass more through one notch side wall than the other. This non-symmetrical flow heats the bottom electrode notch and the magnet wire unevenly causing non-uniform results from one termination to the next.
Another technical need in the art relates to the time, costs and inefficiency of setting up to implement the fusing action and the requirement to move or index either the work piece or the upper and lower fusing heads to join a multiplicity of wires to a multiplicity of pins on a single device. Present apparatus require the operator to set up the pin, wire and lower electrode assembly before each fusing operation. This results in a slow, tedious, costly process with high chance of human error that reduces quality and yields from the system.